A wiper arm is part of a motor vehicle and has a lower end pivoted on the vehicle about an axis that is normally perpendicular to the arm and is provided at its outer end with a pivot pin that extends perpendicular to a plane including the arm's longitudinal axis and lower-end pivot axis. The blade assembly includes at least one elongated elastomeric blade received in a metallic backing strip in turn held in a plurality of secondary yokes that themselves are pivoted on a primary yoke that is traversed by the pivot pin on the wiper-arm outer end. The blade assembly itself normally extends generally parallel to the wiper arm but can pivot on the pivot pin to follow the curvature of the windshield being wiped.
Thus the pivot pin is a nonstandard item whose dimensions are established by the vehicle manufacturer, so that it can correspond to metric or English measurements and vary considerably in size and length. This poses a problem for a manufacturer of wiper-blade assemblies which must be made to fit a large rang of vehicles.
It has been suggested in British patent 2,168,243 to provide differently dimensioned openings in the main yoke for receiving differently dimensioned pivot pins. A latch releasably retains one or the other pivot pin in its associated opening. Such an arrangement can lead to off-center mounting of the wiper arm, causing undesired torque when it is used.